Chapter 10 Internal Regulation

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Chapter 10 Internal Regulation
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Hunger

• Animals vary in their strategies of eating, but
  humans tend to eat more than they need at the
  given moment.
• A combination of learned and unlearned factors
  contribute to hunger.

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Hunger

• The digestive system
• Saliva ? carbs
• Stomach
• Hydrochloric acid ? proteins
• Small intestine
• Large intestine

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Hunger

• The brain regulates eating through messages from
  the mouth, stomach, intestines, fat cells and
  elsewhere.

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Hunger

• The main signal to stop eating is the distention
  of the stomach.
• The vagus nerve
• The splanchnic nerves

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Hunger

• Duodenum
• Cholecystokinin (CCK)

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Hunger

• Glucose, insulin, and glucagon levels also
  influence feelings of hunger (see figures 10-14,
  10-15, 10-6).
• Diabetes

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Fig. 10-14, p. 311
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Fig. 10-15, p. 311
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Fig. 10-16, p. 311
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Hunger

• Long-term hunger regulation is accomplished via
  the monitoring of fat supplies by the body.
• Leptin

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Hunger

• Information from all parts of the body regarding
  hunger impinge into two kinds of cells in the
  arcuate nucleus.

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Hunger

• Output from the arcuate nucleus goes to the
  paraventricular nucleus of the hypothalamus.

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Hunger

• Input from the hunger-sensitive neurons of the
  arcuate nucleus is inhibitory to both the
  paraventricular nucleus and the satiety-sensitive
  cells of the arcuate nucleus itself.

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Hunger

• Output from the paraventricular nucleus acts on
  the lateral hypothalamus.
• The lateral hypothalamus controls insulin
  secretion and alters taste responsiveness.
• Animals with damage to this area refuse food and
  water and may starve to death unless force fed.

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Fig. 10-20, p. 315
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Hunger

• The lateral hypothalamus contributes to feeding

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Fig. 10-22, p. 316
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Hunger

• Ventromedial hypothalamus ? satiety

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Hunger

• People with a mutated gene for the receptors
  melanocortin overeat and become obese.
• Melanocortin is a neuropeptide responsible for
  hunger.
• Prader-Willis syndrome

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Hunger

• Anorexia nervosa
• Bulimia nervosa
• Overeating and Binge-eating Disorder